The six Greenpeace climbers who made the ascent Credit: David Sandison/Greenpeace/PA Wire

The women said their climb was intended to put Shell and other oil companies into the spotlight. The site was reportedly chosen because it overlooked Shell headquarters in London.

The activists aimed to raise awareness of the efforts being made to exploit fossil fuel resources in the Arctic, and the associated safety and and environmental risks.

An activist unfurls a banner near the top of The Shard Credit: Anthony Devlin/PA Wire

A** Shard spokesman said that in the interests of public and protester safety, the viewing platform of the **Shard had been closed to visitors.

But for the spectators following the feat on the ground and via social media around the world, it was a spectacle worth seeing.

Onlookers watch as a group of six protesters scaling the Shard Credit: Sean Dempsey/PA Wire

One climber, Victoria Henry, 32, a Canadian living in Hackney, London, said this morning: "We'll try to hang a huge art installation 310m up that will make Shell think twice before sending their rigs into the Arctic.

"It's going to be really hard work, it's going to be nerve-shredding for all of us and we may not succeed, but we're going to do everything we can to pull it off.